Female rats treated with liothyronine or its solvent (control rats) were given an intravenous injection of [(14)C]-L-histidine. The amount of [(14)C]-histamine in various tissues was measured at 10 min, 60 min and 22 hr after the injection. In control rats the glandular stomach contained large amounts of [(14)C]-histamine at 10 and 60 min, with a sharp decline at 22 hr. The skin contained small amounts at 10 and 60 min, with a slight rise at 22 hr. In rats treated with liothyronine there was more [(14)C]-histamine in the stomach at 10 and 60 min, but not at 22 hr after the injection of [(14)C]-L-histidine. The results support the following conclusions: (1) The glandular stomach in the intact rat forms more histamine than do other tissues; the gastric histamine is in a rapid state of turnover and is likely to contribute substantially to the urinary output of histamine. (2) After treatment with liothyronine the rat has an increased histamine formation in the stomach; this is probably the main cause of the raised urinary histamine excretion in such a rat.

Carbon Isotopes↗

PubMed1964

THE EFFECT OF SODIUM INTAKE ON THE URINARY HISTAMINE IN ADRENALECTOMIZED RATS.

The daily excretion (mug/day) of free histamine has been measured in bilaterally adrenalectomized or sham-operated female rats. In rats developing adrenal insufficiency when kept on a "sodium free" diet, the output of free histamine in the urine fell progressively. The volume of urine was unchanged. In rats with adrenal insufficiency the oral administration of 0.9% saline caused an immediate rise in the urinary excretion of histamine. The rise was sustained for several days. Adrenalectomized rats consuming 43 mg/day of sodium chloride or less developed adrenal insufficiency and the daily output of urinary histamine fell progressively. A sodium chloride intake of 90 mg/day prevented this fall. Adrenalectomized rats kept on 0.9% saline showed no significant changes during the first 7 days after adrenalectomy. From the 8th day onwards the daily output of histamine in the urine rose progressively. After sham operation the daily output of histamine in the urine was not affected by the intake of sodium chloride. Adrenalectomized rats eat less food; a similar restriction of food intake in sham-operated rats decreased the urinary excretion of histamine. The decrease was, however, not as pronounced as in adrenalectomized rats developing adrenal insufficiency. Other sodium salts, but not glucose, had the same effect as 0.9% saline on the urinary excretion of histamine in adrenalectomized rats.

Adrenal Insufficiency↗

PubMed1964